This paper describes a surgeon's clinical experience with the use of prosthetic materials over the course of his 30-year career in orthopedic surgery. In the beginning, a historical review is given detailing the progressive improvement in techniques and in selection of materials for the manufacture of implants, beginning with the use of iron wire in the 18th century and proceeding systematically through the development of an appreciation of the significance of the composition of the metal used, and later, of the nonmetallic material used. A discussion of the progressively more acute appreciation of the two-way-street nature of the problem of compatibility is presented. A development of the cobalt-chrome-molybdenum alloys is briefly reviewed. A development of the austenitic stainless steels and their increasing refinement over the years is also reviewed. The development of the use of titanium and its alloys, beginning in the United Kingdom and proceeding to other countries, is reviewed. The place of thermoplastic and thermosetting resins is then described, beginning with the wide use of the Judet prosthesis following the Second World War and proceeding to the development of the total joint replacement era with the use of polymethyl methacrylate to serve as a grouting compound in the fixation of both metallic and ultrahigh molecular weight polyethylene components. The tissue reaction to wear particles is described and illustrated, demonstrating a new dimension in tissue reaction to implant materials. In conclusion, it is suggested that several of the new biomaterials being developed in various laboratories and universities in the world will find their way into use in surgery. Hopefully a substitute for polymethyl methacrylate will be found, with less mechanical and biological problems. A fundamental understanding of the processes involved in interaction between implant and host is needed for the development of more suitable implant materials in the future.